Command device for a bicycle gear change

Abstract

A command device for a bicycle gear change, comprising: a rotating drum ( 2 ) provided with a rotation axis (x) and being predisposed to rotate in opposite directions in order to wind at least a portion of a change-activating cable ( 3 ) on a lateral surface of the rotating drum ( 2 ); means for rotating, predisposed on command to rotate the rotating drum ( 2 ) in opposite directions according to predetermined angular steps; means for retaining predisposed to hold the rotating drum ( 2 ) in a position in absence of commands made to the means for rotating. The rotation axis (x) of the rotating drum ( 2 ) is perpendicular with respect to an advancement direction of the bicycle, that is, parallel to the rotation axis of the front wheel of the bicycle.

1. A command device for a bicycle gear change, comprising: a rotating drum ( 2 ) provided with a rotation axis (x) and being predisposed to rotate in opposite directions in order to wind at least a portion of a change-activating cable ( 3 ) on a lateral surface of the rotating drum ( 2 ); means for rotating, predisposed on command to rotate the rotating drum ( 2 ) in opposite directions according to predetermined angular steps; means for retaining predisposed to hold the rotating drum ( 2 ) in a position in absence of commands made to the means for rotating; wherein the rotation axis (x) of the rotating drum ( 2 ) is perpendicular with respect to an advancement direction of the bicycle, the means for rotation comprising elastic means ( 24 ), associated to the rotating drum ( 2 ) and predisposed to set the rotating drum ( 2 ) in rotation in an unwinding direction of the cable ( 3 ); a stop mechanism ( 25 ) being actionable between a stop configuration, in which it prevents rotation of the rotating drum ( 2 ) in an unwinding direction of the cable ( 3 ), and a release configuration, in which it enables a rotation of the rotating drum ( 2 ) in an unwinding direction of the cable ( 3 ), in a determined angular step, the stop mechanism comprising: a second cogging ( 26 ), solid in rotation with the rotating drum ( 2 ); a stop cog ( 27 ), mobile between a first position, in which it is engaged to the second cogging ( 26 ) and prevents rotation of the rotating drum ( 2 ) in the unwinding direction of the cable ( 3 ), and a second position, in which it does not engage with the second cogging ( 26 ); an oscillating cog ( 28 ), rotatingly constrained to the stop cog ( 27 ) about an oscillation axis and free to rotate by a determined angle; the oscillating cog ( 28 ) being positioned with respect to the stop cog ( 27 ) in such a way that, in the first position of the stop cog ( 27 ) the oscillating cog ( 28 ) does not engage with the second cogging ( 26 ), while in the second position of the stop cog ( 27 ) the oscillating cog ( 28 ) engages with the second cogging ( 26 ). 
     
     
       2. The command device of  claim 1 , wherein the means for rotating, predisposed on command to rotate the rotating drum ( 2 ) in opposite directions in determined angular steps, comprise a ratchet gear predisposed to rotate the rotating drum ( 2 ) in the direction of winding-on of the cable ( 3 ). 
     
     
       3. The command device of  claim 2 , wherein the ratchet gear and a stop mechanism ( 25 ) are activatable by means of a shaped lever ( 30 ). 
     
     
       4. The command device of  claim 3 , wherein the shaped lever ( 30 ) is rotatingly constrained to a shaped element ( 23 ) about the oscillation axis (b) of the trigger ( 29 ) in such a way as to rotate a trigger ( 29 ) about the axis (b) thereof, the shaped lever ( 30 ) being solidly constrained to the shaped element ( 23 ) with respect to rotation about the rotation axis (x). 
     
     
       5. The command device of  claim 4 , wherein the shaped lever ( 30 ) comprises two portions ( 30   a ,  30   b ) which are hinged one to another about an intermediate hinging axis (s). 
     
     
       6. The command device of  claim 5 , comprising a blocking device which can be activated between a configuration in which it prevents a relative rotation between the two portions ( 30   a ,  30   b ) and a configuration in which it consents relative rotation between the two portions ( 30   a ,  30   b ) of the shaped lever ( 30 ). 
     
     
       7. The command device of  claim 6 , wherein the blocking device comprises a rod ( 33 ) which, at an end thereof, is rotatingly constrained to a portion ( 30   a ) of the two portions of the shaped lever ( 30 ), and at another end thereof is predisposed to engage in a seating which is solidly constrained to the other portion ( 30   b ) of the two portions of the shaped lever ( 30   a ,  30   b ), the rod ( 33 ) being rotatable between a position in which it engages in the seating and prevents relative rotation between the two portions ( 30   a ,  30   b ), and a position in which it does not engage in the seating and enables the relative rotation between the two portions ( 30   a ,  30   b ) of the shaped lever ( 30 ). 
     
     
       8. The command device of  claim 6 , wherein the blocking device ( 33 ) can be activated by a brake lever ( 50 ), the shaped lever ( 30 ) being arranged in such a way that, when the brake lever ( 50 ) is rotated, the blocking device ( 33 ) is brought into the configuration in which it does not prevent a relative rotation between the portions ( 30   a ,  30   b ) of the shaped lever. 
     
     
       9. The command device of  claim 8 , wherein the blocking device is actionable by means of the brake lever ( 50 ), which is predisposed to interfere with an appendage ( 3   a ) of the rod ( 33 ) by rotating the rod ( 33 ) into the position in which it allows relative rotation between the two portions ( 30   a ,  30   b ) of the shaped lever ( 30 ). 
     
     
       10. The command device of  claim 2 , wherein the ratchet gear comprises a first cogging ( 21 ), with cogs thereof in a saw-tooth shape, which first cogging ( 21 ) is arrange peripherally to the rotating drum ( 2 ); a pawl ( 22 ), an end of which is predisposed to engage in the first cogging ( 21 ); a shaped element ( 23 ), constrained to the pawl ( 22 ) and predisposed to activate the pawl ( 22 ) to translate along a direction which is tangential to the rotating drum ( 2 ). 
     
     
       11. The command device of  claim 10 , wherein the pawl ( 22 ) is rotatably constrained to the shaped element ( 23 ) at an opposite end to an end thereof predisposed to engage with the first cogging ( 21 ). 
     
     
       12. The command device of  claim 10 , wherein the shaped element ( 23 ) is rotatable about the rotation axis (x). 
     
     
       13. The command device of  claim 12 , wherein elastic means are predisposed to maintain the pawl ( 22 ) in contact with the first cogging ( 21 ). 
     
     
       14. The command device of  claim 1 , wherein the oscillating cog ( 28 ) engages in the second cogging ( 26 ) at a first end of a rotation angle thereof and is drawn in rotation by the rotating drum ( 2 ) up to a second end of the rotation angle thereof, at which it stops and also stops a rotation of the rotating drum ( 2 ). 
     
     
       15. The command device of  claim 14 , wherein the elastic means are predisposed to rotate the oscillating cog ( 28 ) from the second end towards the first end of the rotation angle. 
     
     
       16. The command device of  claim 1 , wherein the stop cog ( 27 ) is solidly constrained to a trigger ( 29 ) which trigger ( 29 ) on command oscillates about an axis (b), the oscillating cog ( 28 ) being rotatingly constrained to the trigger ( 29 ), the trigger ( 29 ) being predisposed on command to activate the stop cog ( 27 ) in displacements between the first position thereof and the second position thereof.